One of the most striking and debilitating features of autism is the profound impairment in social and emotional functioning. In recent years, the emergence of modern cognitive neuroscience techniques has led to a greater understanding of the neural bases of such abilities in healthy control subjects. However, very little is known regarding the neural bases of the impaired social and emotional functioning in individuals with autism. In the present series of studies, the functioning of the default network was examined across various task and non-task conditions. This network is comprised of the medial prefrontal cortex (MPFC), retrosplenial cortex/posterior cingulate cortex (RSC/PCC), precuneus (PrC), and angular gyrus (ANG), among other regions, and typically activates during performance of tasks of a social, emotional, or self-referential introspective nature (e.g., social perception, emotion processing, mentalizing tasks, autobiographical recall, etc.). Furthermore, the default network maintains high levels of metabolic activity at rest, in the absence of any task demands, suggesting that ongoing unconstrained thoughts of a social, emotional, and introspective nature might be the natural, default state of the mind. In Chapter II, the default network activity in autism was examined during a resting condition and an implicit emotion processing condition. In both of these conditions, reduced levels of activity were found in regions of the default network. Furthermore, the degree of resting functional abnormality in the MPFC correlated to a clinical measure of social impairment. In Chapter III, these findings were extended by demonstrating reduced levels of functional connectivity within the default network at rest, with the reduction being particularly pronounced in the MPFC and left ANG. These reductions were not a pervasive feature of the resting brain, as no abnormality was found in a different network (i.e., the dorsal attention network). In Chapter IV, in order to determine whether default network regions are capable of being engaged under particular experimental circumstances, activity was measured during an explicitly-defined and experimentally-constrained self- and other-reflection task. Although subtle task-specific abnormalities in autism were found, the overall level of functional activity across all conditions was remarkably similar between groups. All together, these findings suggest that while the default network often does not engage under typical circumstances in individuals with autism, it is in fact capable of responding, given particular highly- specified experimental constraints. Further investigation of the nature of this engagement deficit might prove instrumental in elucidating the causes of autism, and may help to refine behavioral treatments

Although gaze can be directed at any location, different locations in the visual environment vary in terms of how likely they are to draw another person’s attention. One could therefore weigh incoming perceptual signals (e.g., eye cues) against this prior knowledge (the relative visual saliency of locations in the scene) in order to infer the true target of another person’s gaze. This Bayesian approach to modeling gaze perception has informed computer vision techniques, but we assess whether it is a good model for human performance. We present subjects with a “gazer” fixating his eyes on various locations on a 2-dimensional surface, and project an arbitrary photographic image onto that surface. Subjects judge where the gazer is looking in the image. A full Bayesian model, which takes image saliency information into account, fits subjects’ gaze judgments better than a reduced model that only considers the perceived direction of the gazer’s eyes.

Social interactions serve as the primary training ground for many of a child’s positive cognitive and developmental abilities. Parent responsiveness has been identified as one key mechanism through which children gain more mature skills, but the question of how children elicit responses from their parents remains to be fully investigated. In this study, we utilized head-mounted eye trackers to track moment-by-moment shifts in gaze, manual action, and speech during parent-child toy play. This allowed us to identify the moments preceding a parent response and the type and timing of the parent’s response relative to the child’s behaviors. We found that child events of attention and action – where they were both touching and looking at a toy – were more successful in eliciting parent responses overall and in eliciting multimodal parent responses than events of just child look or child touch. The parent’s latency to respond to their child differed by event type and duration, suggesting that child behaviors influence parent responses. Implications and future directions are discussed.

Sustained attention (SA) is a critical skill in which a child is able tomaintain visual attention to an object or stimulus. The current studyemploys head-mounted eye trackers to study the cognitive processesunderlying SA by analyzing micro-level behaviors during parent-child social interactions in both typically and atypically developingchildren. Specifically, we examined the role of parent look, parenttouch, and child touch on SA duration. Results show that parent lookequally influences SA in both groups, while parent touch is morecritical for SA for TD children and the child’s own touching is morecritical for SA in children with autism spectrum disorder (ASD).Implications of different pathways to maintain SA between typicallydeveloping children and children with ASD are discussed.

The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neural correlates of co-occurring psychopathology; 284 diffusion imaging datasets are also included. It is anticipated that these enhancements will contribute to unraveling key sources of ASD heterogeneity.